When can a bus driver engage the bus's hazard lights?

Answer: B — When stopped in an emergency or for passenger safety

Engaging the bus's hazard lights is an important safety practice that is specifically intended for situations where there is an immediate need to alert other drivers to unusual conditions or potential hazards. When a bus driver is stopped in an emergency or for passenger safety, activating the hazard lights serves to inform other road users that the vehicle is not moving and may pose an obstruction or require additional caution. This is especially crucial in situations where the bus might be in a dangerous location, such as on the side of the road or in both lanes of traffic, allowing other drivers to recognize the situation and adjust their driving accordingly. In contrast, using hazard lights in other contexts, such as while waiting at a traffic light or parked in a designated bus lane, does not effectively communicate a need for caution and could lead to confusion among other drivers. Furthermore, while hazard lights might be employed in construction zones for additional visibility, the primary function is still to signal an unusual or hazardous situation rather than simply indicating that a vehicle is temporarily stopped or waiting.